In a wireless network, e.g., an ad hoc network, in which a network infrastructure does not exist, a terminal has to combat certain challenges in order to set up a communication link with another peer terminal. One challenge is to make the terminals in the vicinity to be synchronized to a common timing and/or frequency reference. A common timing and/or frequency reference is crucial for the terminals to establish communication links. For example, in an ad hoc network, when a terminal just powers up or moves into a new area, the terminal may have to first find out whether another terminal is present in the vicinity before any communication between the two terminals can start. The general solution is to let the terminal transmit and/or receive signals according to certain protocol. However, if the terminals do not have a common timing notation, it is possible that when a first terminal is transmitting a signal and a second terminal is not in the receiving mode, the transmitted signal does not help the second terminal to detect the presence of the first terminal.
In view of the above discussion, it should be appreciated that there is a need for new and improved ways for identification, acquisition, and/or synchronization, especially in a wireless system in which the network infrastructure may not be available.